Gait feedback system

ABSTRACT

A system may be provided for incorporation in an article of footwear that has an upper coupled to a sole, where the sole has an insole and an outsole and the upper and the insole define an interior space for receiving a foot of a user. The system may include a device configured to be coupled to the footwear beneath the user&#39;s foot and a structure for fixing the device in place in a predetermined position in the footwear. In such system, the structure may include a compressible portion coupled to a substantially incompressible portion, and the device may be directly supported by the hard plastic portion of the structure to provide a feedback signal to the user when a pressure applied to the device by the user&#39;s foot exceeds a threshold value.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. patent application Ser. No. 16/111,096, entitled GAIT FEEDBACK SYSTEM, filed Aug. 23, 2018, now allowed; which claims priority to U.S. Provisional Patent Application Ser. No. 62/549,364, filed Aug. 23, 2018; which applications are hereby incorporated by reference in their entireties as if fully set forth herein, including Specification. Figures, Claims, and all other matter.

FIELD OF THE DISCLOSURE

The field of the present disclosure includes a system for providing to a wearer of a shoe a sensory feedback indicating characteristics of the gait and stance of the wearer, including the force of heel strike and overstriding. Various configurations of embodiments of the present disclosure may notify the wearer when a force at the wearer's foot exceeds a desired threshold at a specific or general area of the foot. The notification through the sensory feedback may be with regards to an initial foot strike or at any time the foot is bearing some weight during walking, running or standing. The field also includes the system for providing the sensory feedback as an audible sound or as haptic feedback.

BACKGROUND AND SUMMARY OF THE DISCLOSURE

Devices have been proposed for use at a toe-end in a child's shoe to produce a sound to indicate when the child's foot has grown over the device in the toe-end. In particular, U.S. Pat. No. 5,014,041 to Rosen describes a Shoe Fitting System for children's shoes, and shows in FIGS. 8 and 9 a spring 66 at the toe-end of the shoe that begins clicking when the child's foot grows over the spring. FIGS. 10 and 11 of Rosen show electrical pressure switches in the heel 74 (to check that the child's foot is not shifted forward in the shoe) and toe 76 connected to a circuit to make an audible response, again as the child's foot grows over the toe-end switch. The disclosure of Rosen does not provide any teaching relating to the wearer's foot-strike mechanics in a walking or running gait.

A dancer's shoe is disclosed in U.S. Pat. No. 621,892 to Azzimonti, with a bell b1 in heel B for the purpose of entertainment. The shoe has a striker b2 that rings bell b1 only when the dancer stomps his or her foot. Like Rosen, the disclosure in Azzimonti lacks any suggestion for how to provide the wearer with feedback on the wearer's foot-strike mechanics in a walking or running gait. Similarly, U.S. Pat. No. 4,253,254 provides a squeaker in the heel of a shoe, generally designed to make noise on each step, again without feedback on characteristics of the wearer's foot-strike mechanics.

Several patents, such as U.S. Pat. No. 7,997,007, disclose electronic systems, including heel and toe sensors coupled to a computer and/or amplifier that may produce tones indicating a particular foot-strike pattern. However, such a system is complex, expensive, and difficult for a user to operate.

A system according to one or more embodiments of the present disclosure provide a shoe or insole insert with a mechanical structure producing audio and/or haptic feedback on the wearer's foot-strike mechanics and the wearer's stance during certain conditions.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a pictorial side view of a person running with overstriding.

FIG. 2 is a pictorial side view of a person running without overstriding.

FIG. 3 is an overhead view of a feedback device in accordance with an embodiment of the present disclosure in a shoe with an insole insert.

FIG. 4 is a perspective view of the feedback device of FIG. 3 with the insole insert out of the shoe.

FIG. 4a is a perspective view of an example spring of the feedback device, with the spring in place.

FIG. 5 is a perspective view of the spring and the base of the feedback device, with the spring in place.

FIG. 5a is a perspective view of another example of a base for the feedback device, without the spring in place.

FIG. 6 is a perspective view of the spring and the base of the feedback device, with the spring flipped out of the way to show more of the base.

FIG. 6a is a perspective view of the spring of FIG. 4a and the base of FIG. 5a for the feedback device, with the spring in place.

FIG. 7 is a cross-sectional view of the feedback device with an alternatively configured base.

FIG. 8a is a side cross-sectional view of a layout of a seesaw configuration for an embodiment of the present disclosure with the lever arm not depressed.

FIG. 8b is a side cross-sectional view of a layout of a seesaw configuration for an embodiment of the present disclosure with the lever arm partially depressed to the point it is about to trigger the spring.

FIG. 8c is a side cross-sectional view of a layout of a seesaw configuration for an embodiment of the present disclosure with the lever arm depressed to the extent it has pushed the pressure point sufficiently to trigger the spring, inverting the dimpled portion and providing feedback to the wearer.

FIG. 9a is a side cross-sectional view of a layout of a slider configuration for an embodiment of the present disclosure with the slider in the non-actuated position.

FIG. 9b is a side cross-sectional view of a layout of a slider configuration for an embodiment of the present disclosure with the slider moved toward the actuated position.

FIG. 9c is a side cross-sectional view of a layout of a slider configuration for an embodiment of the present disclosure with the slider in the actuated position and the spring inverted.

FIG. 10a is a side cross-sectional views of a layout of an inverter configuration for an embodiment of the present disclosure with the actuator not depressed.

FIG. 10b is a side cross-sectional views of a layout of an inverter configuration for an embodiment of the present disclosure with the actuator partially depressed.

FIG. 10c is a side cross-sectional views of a layout of an inverter configuration for an embodiment of the present disclosure with the actuator sufficiently depressed to invert the spring.

DETAILED DESCRIPTION OF THE DISCLOSURE

Embodiments of the present disclosure are directed to providing feedback to a wearer of a shoe or other footwear, informing the wearer about force exceeding a desired threshold at a specific or general area of the foot. The sensory feedback may be with regards to an initial foot strike or at any time the foot is bearing some weight during walking, running or standing. For example, feedback regarding gait, foot strike pattern, or weight distribution through a ground contact phase. Additional examples include feedback about whether the wearer is flat footed while standing.

Some embodiments of the present disclosure provide the feedback to the wearer about his or her gait while running or walking. The device may provide a measure, at least as a single-point indicator of exceeding a threshold of a force vector, i.e., a force and an angle at impact, and/or force and angle during ground contact as weight is transferred forward on the foot.

One example of such feedback is to provide a signal when the wearer overstrides. i.e., when, during running or walking, a foot is lifted and moved forward and, on impact with the ground, lands in front of the knee with the tibia not vertical. Conversely, the absence of feedback from the device informs the wearer of a non-overstriding condition, providing negative reinforcement to the wearer of the preferred gait or weight distribution. In negative reinforcement, a desired response or behavior is strengthened by stopping, removing or avoiding a negative outcome or aversive stimulus. FIGS. 1 and 2 illustrate this in a running gait, in both cases at the point where foot F is just being brought back into contact with the ground G after being lifted and moved forward. Additionally, embodiments of the present disclosure may be configured to provide positive reinforcement to the wearer, for example, by providing a feedback signal to the wearer while running or walking with the desired gait or in a desired stance.

FIG. 1 illustrates a running gait where person W overstrides with a heel strike. The location where foot F hits ground G is forward of knee K by an overstride distance OSD. In this particular illustrated circumstance, the person's heel H is the first portion of foot F to strike the ground with the sole of the foot not horizontal to ground G. The angle of the tibia in the overstriding condition is shown by arrow OSA, which is not near vertical. In this case of overstriding with heel strike, the force of the strike at the heel is significant and is associated with a braking force that tends to decelerate the person's body. Other circumstances and foot strike patterns may also involve overstriding, and the angle of the tibia (lower leg) at impact is understood to be a determinant of overstriding. That is, the tibia being near vertical at ground impact indicates a stride length that typically is preferred, although this varies for different running styles. Generally, a heel strike is frequently an aspect of overstriding, although it is possible to overstride with a midfoot or forefoot strike pattern. Embodiments of the present disclosure may be used as a tool to train the wearer towards the practice of a gait that is preferred for a particular running style.

FIG. 2 illustrates, at the point of ground-contact of the forward foot, a running gait without overstriding. Here the person's foot F strikes the ground with heel H behind knee K and the tibia is near vertical. The example of a non-overstriding condition illustrated in FIG. 2 includes that foot F strikes the ground in a flat orientation, i.e., with the sole parallel to the ground also known as a midfoot strike, with the weight distributed roughly evenly between the heel and forefoot. Alternatively, in the non-overstriding condition the forefoot might strike before the heel (known as a forefoot strike), or the heel might strike slightly before the forefoot. In some instances of a non-overstriding condition the foot is striking the ground roughly parallel to the ground, although this varies runner to runner. In the non-overstriding condition the braking force of strike at the heel is typically small or insignificant relative to the overall impact of the foot, and the downward force at the heel is less than or equal to the downward force at the forefoot.

Overstriding is understood to impose suboptimal energy costs on a runner, and a runner wanting to stop overstriding may be assisted by a system that informs the runner as overstriding is occurring. Similarly, informing a person of a detrimental foot strike pattern as the pattern is occurring may be useful for correcting such patterns or undesirable weight distribution during ground contact.

As shown in FIG. 3, a system 100 in accordance with one or more embodiments of the present disclosure may include a shoe 102 that includes an upper 104 coupled to a sole 106. Sole 106 includes an insole 108 and an outsole 110 (FIG. 1). Inside shoe 102, upper 104 and insole 108 define an interior space 112 for receiving a foot F of a user W (see FIGS. 1 and 2). Insole 108 may include an insert 114, typically made of a soft foam, such as EVA.

A feedback device 116 may be positioned in shoe 102 between the wearer's foot and sole 106 of the shoe, for example below the heel of the wearer's foot, and preferably the rear portion of the heel area, as shown in FIG. 3. Insert 114 may include a cutout area 118 to receive and fix in location the feedback device. Feedback device 116 may include a base 120 supporting a spring 122 configured to provide audio and haptic feedback to the wearer under certain conditions, such as overstriding.

FIG. 4 shows feedback device 116 still within insert 114 but with both removed from the shoe. Feedback device 116, base 120, spring 122, and/or insert 114 may be built into the shoe or one or more of these may be removable, as illustrated by FIG. 4.

Cutout area 118 may be shaped to receive base 120, which in turn may support spring 122. Insert 114 and base 120 may provide a structure for fixing spring 122 in place in a predetermined position in the shoe, e.g., in the heel area of the shoe where it can provide feedback to the wearer on whether or not the wearer is overstriding. Insert 114 is typically is made of a compressible material, such as EVA foam or similar material generally selected for the wearer's comfort. Base 120 is typically made of a substantially incompressible material, such as a hard plastic. e.g., ABS, which may provide a direct, substantially fixed support to spring 122, allowing spring 122 to respond with feedback to the pressure that the wearer's heel exerts on the spring and the base.

Base 120 and spring 122 are shown separate from the insert in FIG. 5. Base 120 may be substantially rectangular and include forward edge 124, side edges 126 a and 126 b, and rear edge 128. Spring 122 may be deployed on base 120 with the spring's forward edge 130 and side edges 132 a and 132 b fitted between the corresponding edges of base 122. A rear edge 134 of spring 122 may rest on edge 128 of base 120.

Typically spring 122 is a substantially flat piece of metal. e.g., steel, that may be formed by stamping. Spring 122 may include an upwardly dimpled portion 140 that can deform abruptly downwardly under a specified pressure or force, and, in doing so, provide an audible sound, such as a click sound, and a haptic feedback indicating the deformation. The abrupt deformation is typically a characteristic of the dimpled steel, although it may be formed for a more gradual deformation, or formed with different structure, and detect the pressure or force and provide feedback within the scope of the present disclosure.

Spring 122 may, for example, be a tactile dome spring and may be designed to meet one or more performance criteria. These criteria may include a specific actuation force, the physical dimensions of the spring, and the quality of the sound produced by the spring at actuation. For example, the spring actuation force, expressed as a weight may be about 8.8 pounds or 4,000 grams and the spring may have a height of 1.5-mm and width of 25-mm. The spring may be tuned to produce a sound at actuation or alternatively may be tuned to be substantially silent. In either case, the spring may offer haptic feedback to the wearer at actuation. An example of a dome spring 122 a is shown in FIG. 4a . Such a dome spring may be obtained. e.g., from Snaptron: see https://www.snaptron.compart-number/gx252000/.

As an example of operation in use, if the wearer is running with an overstride that includes a heel strike pattern, the wearer's heel on each foot strike will apply pressure at dimpled portion 140 of spring 122, causing deformation at dimpled portion 140, producing an audible click sound and a haptic feedback of the dimpled portion dropping relative to the rest of the spring and moving downwardly away from the wearer's heel. As the spring deforms away from the wearer's heel the user may feel this as a sudden drop underneath that part of their foot. A typical overstride involves the wearer's heel striking first, although this is not always the case, but the overstriding is expected to provide pressure to spring 122. The strength of the material and dimensions of spring 122 and its dimpled portion 140, as well as the supporting geometry and the hardness of base 120, may be selected for detecting when the pressure applied to the device by the user's foot exceeds a threshold value that is characteristic of an undesired gait. For example, the threshold value may be selected to detect heel striking.

As shown in FIG. 5, spring 122 rests on base 120 and may be held in place by any suitable means. For example, adhesive tape 142 provides a hinged connection of spring 122 to base 120.

The supporting geometry of base 120 is shown in FIG. 6, where spring 122 has been flipped over forward edge 124. Adjacent forward edge 124, base 122 provides a ridge 144 for supporting spring 122 at edge 130 in conjunction with the support by base edge 128 of spring rear edge 134. A recessed portion 146 of base 120 extending between base edges 124 and 128 may facilitate spring 122 flexing and deforming at dimpled portion 140 under pressure from the wearer's foot.

With reference to FIGS. 5 and 6, either or both of spring 122 and base 120 may be varied to adjust the threshold at which the spring deforms. For example, the diameter of the dimpled portion may be varied and/or the base's span between its edges that support the spring may be varied. Each of these affect the force at which the spring deforms, in addition to other characteristics as described above.

A base 120 a is shown in FIG. 5a having an alternative construction that may be used, e.g., with dome spring 122 a of FIG. 4a . Dome spring 122 a may be operational for actuation in base 120 a on a substantially flat surface 146 a in base 120 a. The supporting geometry of base 120 a is similar to base 120. Base 120 a provides a ridge 144 a that may substantially surround flat surface 146 a and the ridge may provide four corners for supporting each of the four corners of spring 122 a, as best seen in FIG. 6a . Spring 122 a may be held in place in base 120 a by any suitable means, such as shrink-wrap material 142 a. Thus, base 120 a may facilitate spring 122 a flexing and deforming under pressure from the wearer's foot similar to the operation of the base 120 and spring 122 a.

The foregoing embodiment of the present disclosure is an example of how a feedback device provides information to the wearer about the wearer's foot strike pattern. This particular example is directed toward detection of a heel strike pattern, which may be useful for the wearer's eliminating, reducing, or changing that foot strike pattern and/or an overstriding gait. Variations on the structure may provide additional information about the wearer's foot strike pattern and gait. Embodiments of the present disclosure encompass the providing of a wide variety of information about the strike pattern and gait. Feedback devices in accordance with the present disclosure may be arranged to detect and inform the wearer about the angle of the foot relative to the ground at impact in either or both of the sagitall plane and the coronal plane. That is, feedback devices may be used in detecting heel, midfoot, and forefoot strikes, as well as striking on the inside or outside of the foot, and/or characteristics of the foot's pronating and/or supinating during the period of contact with the ground. The feedback devices may detect the undesired weight distribution during impact and/or during the period of ground contact as a function of the wearer's pace. For example, the threshold value may be set so that a low impact heel strike at walking pace does not trigger the feedback device, while a heel strike at a faster pace will trigger the feedback device.

FIG. 7 is a cross-sectional view of the feedback device with an alternatively configured base 120 a for spring 122. Base 120 a includes side edges 150 a and 150 b with a recessed or cutout portion 152 therebetween providing support for spring 122 while facilitating deformation at dimpled portion 140. Base 120 a may also include a trigger 154 with a hinge 156, which may be integrally formed with the rest of base 120 a, coupling trigger 154 to one of edges 150 a or 150 b. Materials, geometry, and operation of base 120 a may be otherwise substantially similar to base 120, while trigger 154 and hinge 156 may provide additional selectable variations for setting the threshold value for device 116 to provide feedback to the wearer.

The foregoing embodiments generally provide the feedback device with a button on a spring where a force directed roughly perpendicularly to a raised section of the spring causes the spring to deform, and alternative transformations of the force may be provided for particular applications in embodiments of the present disclosure. For example, as shown in FIGS. 8a-c , a lever configuration 802 may include a fulcrum 804 and a pressure point 806 on a lever arm 808 that applies the force to the raised section 140 of the spring 122 during an undesired foot strike pattern. As shown in the progression of FIGS. 8a, 8b, and 8c , the lever arm 810 is not depressed in 8 a; the lever arm is partially depressed in 8 b to the point it is about to trigger the spring; and in 8 c the lever arm's depression has pushed the pressure point sufficiently to trigger the spring and invert dimpled portion 140, providing feedback to the wearer. In this embodiment the direction of the force may be reversed and/or more or less force may be required to deform spring depending on the position of the fulcrum nearer or further out on lever arm, as best suited for a particular application. In such configuration, the fulcrum and/or pressure point may be moved to adjust the threshold value for spring deformation. In the embodiment depicted in FIGS. 8a-c the seesaw lever provides the fulcrum in the middle and the dimpled portion of the spring protrudes downward and is positioned above the unloaded lever arm, while other embodiments may of such seesaw lever may receive a force from below and transfer that force to an upwardly facing dimpled portion.

In another alternative embodiment, depicted in FIGS. 9a-c , a slider configuration 902 may include a sliding track 904 on rollers 910 or other bearing surface may be arranged over the raised section 140 of the spring 122, typically to slide parallel to the spring surface. The track and spring are shown in a nominal position in 9 a; and partially slid in 9 b, almost to the point of triggering the spring; and in the triggered position in 9 c, providing feedback to the wearer. In such configuration, overstriding may cause the sliding track to move forward, in turn causing the spring to deform. The embodiment may be particularly useful in detecting the runner's braking force in an undesired gait, such as an overstriding condition.

Another embodiment is shown in FIGS. 10a-c , where an inverter mechanism 1002 provides for a downward force on spring 122 to trigger a downwardly-facing dimpled portion 140 in an upward direction. Typically with inverter 1002, the wearer's foot is positioned over a bar 1004 overlaying spring 122 and inverter 1002 also has a base 1006 including a raised portion 1008 beneath spring 122 with raised portion 1008 abutting dimpled portion 140 of spring 122. Alternatively, the wearer's foot, sock, and/or a layer of foam, fabric, or similar shoe material may directly overlay spring 122 without bar 1004. In a nominal position as shown in FIG. 10a , the wearer's foot and/or bar 1004 are above spring 122, which is in the non-triggered condition. A force downwardly on bar 1004 presses on spring 122, as shown in FIG. 10b , pressing dimpled portion 140 against raised portion 1008. As shown in FIG. 10c , a sufficient downward force on bar 1004 (and/or an upward force or resistance at raised portion 1008) causes spring 122 to trigger, providing feedback to the wearer.

Embodiments of the present disclosure encompass devices for detecting when pressure exceeds a threshold value in any portion of the shoe sole. The detection may provide sensory feedback when exceeding the threshold value indicates a proper gait as well as an improper gait, depending on the particularly application. For example, a feedback device may be located for the detection of overpronation, underpronation, and/or proper pronation of the wearers foot, and the feedback device may be configured to provide the sensory feedback on any of the conditions. Other forms of sensory feedback may be used, such as a vibratory haptic feedback.

The feedback device of the present disclosure may be inserted into any footwear or be built into any footwear. This includes any shoe, boot, sandal, sock, or any insert for any of these, including anything that can be positioned beneath the foot.

The feedback device of the present disclosure may be incorporated into instructional and rehabilitation protocols of podiatrists/physical therapists/coaches and may be used to educate/guide patients and athletes toward proper mechanics.

It is believed that the disclosure set forth herein encompasses multiple distinct inventions with independent utility. While each of these inventions has been disclosed in its preferred form, the specific embodiments thereof as disclosed and illustrated herein are not to be considered in a limiting sense as numerous variations are possible. Each example defines an embodiment disclosed in the foregoing disclosure, but any one example does not necessarily encompass all features or combinations that may be claimed. Where the description recites “a” or “a first” element or the equivalent thereof, such description includes one or more such elements, neither requiring nor excluding two or more such elements. Further, ordinal indicators, such as first, second or third, for identified elements are used to distinguish between the elements, and do not indicate a required or limited number of such elements, and do not indicate a particular position or order of such elements unless otherwise specifically stated. 

What is claimed is:
 1. A gait feedback system for footwear, comprising: a compressible insert including an upper insert side and a lower insert side; and a sensory feedback device including a hard base and a spring, the spring having a first end and a second end, the first end of the spring resting on the hard base and the spring being held in place on the hard base, the sensory feedback device being fixed inside the compressible insert between the upper insert side and the lower insert side with the hard base being nearer the lower insert side than the spring and the second end of the spring being nearer the upper insert side than the first end of the spring; wherein: the compressible insert is configured for insertion into an interior space defined by an upper of an article of footwear and an inner surface of a sole of the article of footwear so that the lower insert side is adjacent to the inner surface of the sole; the second end of the spring is separated from the interior space by a layer of a compressible material when the compressible insert is placed into the interior space with the lower insert side adjacent to the inner surface of the sole; and the spring is configured so that when the spring is compressed by force to bring the first end and the second end closer together, the spring deforms abruptly producing a sensory feedback signal in response to the force exceeding a predetermined force threshold value, whereby a wearer of the footwear receives the sensory feedback signal when the force applied by a foot of the wearer on the second end exceeds the threshold value.
 2. The gait feedback system of claim 1, wherein the compressible insert is shaped as an insole and the lower insert side conforms to the inner surface of the sole.
 3. The gait feedback system of claim 2, wherein the spring is a dome spring comprising a dimpled portion at the second end.
 4. The gait feedback system of claim 3, wherein the dome spring is made of steel.
 5. The gait feedback system of claim 3, wherein the compressible insert comprises a heel area and the sensory feedback device is fixed in the heel area.
 6. The gait feedback system of claim 5, wherein the hard base comprises ABS.
 7. The gait feedback system of claim 5, wherein the hard base is made of hard plastic material.
 8. The gait feedback system of claim 7, wherein the compressible insert comprises foam.
 9. The gait feedback system of claim 7, wherein the compressible insert comprises EVA.
 10. The gait feedback system of claim 5, wherein the hard base comprises portions defining a flat surface and a ridge configured to support the dome spring on the flat surface at an edge of the base.
 11. The gait feedback system of claim 5, wherein the compressible insert comprises portions defining a cutout for receiving the sensory feedback device.
 12. The gait feedback system of claim 5, wherein the sensory feedback signal comprises an audible sound produced by the spring when the spring deforms abruptly in response to the force exceeding the predetermined force threshold value.
 13. The gait feedback system of claim 5, wherein the sensory feedback signal comprises a haptic signal produced by the spring when the spring deforms abruptly in response to the force exceeding the predetermined force threshold value.
 14. The gait feedback system of claim 5, wherein the predetermined force threshold value is equivalent to the weight of about 4,000 grams.
 15. The gait feedback system of claim 5, wherein the sensory feedback device further comprises a piece of an adhesive tape or shrink-wrap material holding the spring in place on the hard base.
 16. A gait feedback system for footwear, comprising: a compressible insert including an upper insert side and a lower insert side; and a sensory feedback device including a hard base and a spring, the spring having a first end and a second end, the first end of the spring resting on the hard base and the spring being held in place on the hard base, the sensory feedback device being fixed inside the compressible insert between the upper insert side and the lower insert side with the hard base being nearer the lower insert side than the spring and the second end of the spring being nearer the upper insert side than the first end of the spring; wherein: the compressible insert is configured for insertion into an interior space defined by an upper of an article of footwear and an inner surface of a sole of the article of footwear so that the lower insert side is adjacent to the inner surface of the sole; the sensory feedback device at the second end of the spring is exposed to the interior space when the compressible insert is placed into the interior space with the lower insert side adjacent to the inner surface of the sole; and the spring is configured so that when the spring is compressed by force to bring the first end and the second end closer together, the spring deforms abruptly producing a sensory feedback signal in response to the force exceeding a predetermined force threshold value, whereby a wearer of the footwear receives the sensory feedback signal when the force applied by a foot of the wearer on the second end of the sensory feedback device exceeds the threshold value.
 17. The gait feedback system of claim 16, wherein: the compressible insert is shaped as an insole and the lower insert side conforms to the inner surface of the sole; the spring is a dome spring comprising a dimpled portion at the second end; the compressible insert comprises a heel area and the sensory feedback device is fixed in the heel area; the hard base is made of hard plastic material; and the compressible insert comprises foam.
 18. The gait feedback system of claim 17, wherein the sensory feedback device further comprises a piece of an adhesive tape or shrink-wrap material holding the spring in place on the hard base.
 19. The gait feedback system of claim 17, wherein the hard base comprises portions defining a flat surface and a ridge configured to support the dome spring on the flat surface at an edge of the base.
 20. A combination comprising the gait feedback system of claim 17 and the article of footwear.
 21. A gait feedback device for footwear, comprising: a slider; rollers; and a spring; wherein: the slider comprises a track supported by the sliders and siding on the sliders over and parallel to the spring, and a bump protruding from the truck towards the spring; and the spring comprises a straight portion and a raised portion extending from the straight portion towards the track, the bump clearing the straight portion when the bump is over the straight portion, the bump pushing the raised portion when the slider slides on the rollers parallel to the spring and brings the bump into impingement on the raised portion thereby deforming the spring and providing a feedback signal to a wearer of the article of footwear, the feedback signal being indicative of undesirable gait.
 22. The gait feedback of claim 21, further comprising a body fixing the rollers and the spring.
 23. The gait feedback device of claim 22, wherein the feedback signal is indicative of overstriding.
 24. The gait feedback device of claim 23, wherein the slider further comprises a projection at a first end, the projection extending from the track in the same direction as the bump.
 25. The gait feedback of claim 22, wherein the projection prevents the slider from sliding forward beyond a triggered position in which the bump impinges on the raised portion. 